The present invention relates to a spinning reel for fishing.
A spinning reel for fishing is arranged as follows: a semi-circular bail is mounted through support members onto the leading ends of a pair of support arms of a rotor so as to be movable between a fishing line take-up position side and a fishing line play-out position side. A line roller for guiding a fishing line from the top end of a fishing rod toward a spool during taking-up or winding of the fishing line is mounted on one of the support members.
After the bail is raised up to the fishing line take-up position, the rotor is rotated in a fishing line take-up direction by operating a handle, so that the fishing line is wound through the line roller around the spool which can be reciprocated back and forth in linking with the rotation of the rotor. On the other hand, after the bail is reversed to the fishing line play-out position side, terminal tackles are cast, so that the fishing line wound around the spool is played out from the spool in a spiral manner.
Since this type of line roller is formed by grinding ceramics material, brass or the like, the finished surface of the line roller is rough and, therefore, if the fishing line is used together with the line roller for a long period of time, then there is a fear that the fishing line can be damaged and cut by the rough surface of the line roller.
In view of this, recently, in order to not only relieve the surface roughness of the line roller to thereby prevent the fishing line against cutting but also enhance the surface hardness of the line roller to thereby prevent the line roller against wear due to the fishing line, there is proposed a line roller in which a base body formed of metal material is plated with a ground layer made of hard chromium, nickel or the like and, after then, onto the thus treated base body, there is applied a coating layer formed of nitride ceramics such as TiN, AlN or the like or carbide ceramics such as TiC, SiC or the like (see Japanese Patent Publication No. Hei. 8-280305).
According to the above-mentioned line roller, when compared with the conventional line roller that is formed simply by grinding ceramics material, brass or the like, it is possible to reduce the occurrence of the damaged fishing line but, in fact, the occurrence of the damaged fishing line cannot be eliminated completely.
Here, FIG. 12 shows the measured results of the surface roughness of the above-mentioned line roller with a coating layer formed of TiN placed on the surface thereof. In particular, when the measurement was made under the illustrated setting conditions, there were obtained the measured values such as Rz=0.75 .mu.m, Ry=1.06 .mu.m, and also there was obtained a roughness curve which is shown in FIG. 12.
By the way, adding some explanation as to FIG. 12, as known well conventionally, the term "roughness curve" means a curve which is obtained by removing surface wave components having longer wavelengths than a given wavelength from a section curve (a cut obtained by cutting the surface of the line roller along a plane at right angles to a surface to be measured; contour) Also, in FIG. 12, reference characters Ra, Rz, and Ry are respectively parameters specified in JISB0601-1994, that is, Ra, Rz, and Ry respectively stand for "arithmetic mean roughness", "ten-points mean roughness", and "maximum height" in the measurements of the surface roughness.
In FIG. 12, Rz. DIN, Ry. DIN, RK, Rpk, Rvk, Mr1, and Mr2 are respectively other parameters than those specified in the JIS30601-1994, that is, they represent "ten-pointsmean roughness (which can be obtained from the whole evaluation length)", "maximum height (which can be obtained from the whole evaluation length)", "effective load roughness", "initial wear height", "oil collecting depth", "load length rate 1", "load length rate 2" in the measurements of the surface roughness, respectively.
Accordingly, in the above-mentioned line roller, even if a coating layer is disposed on the outer surface thereof using TiN, Rz=0.75 .mu.m is its limit and it is impossible to make the surface of the line roller smoother than the limit value.
Also, since a spinning reel has a structure that, as the rotor is rotated, the fishing line containing seawater, sand, foreign objects and the like is contacted with the line roller and is then guided onto the spool, the seawater, sand and the like invade and stick to the inside of the line roller from the side portions thereof, so that the inside of the line roller is easy to corrode. Therefore, in order to maintain the stable function of the line roller, it is essential to maintain the line roller at an opportune moment (for example, timely cleaning or lubrication is essential).
However, as described above, in the present state of the conventional line roller, the line roller is formed by grinding the ceramics material, brass or the like and the coating layer is deposed on the surface of the line roller to thereby show a metallic-style appearance.
Therefore, it is difficult to confirm the conditions (such as the degree of corrosion of the inside of the line roller, degree of invasion of foreign objects, and the like) of the inside of the line roller, which makes it impossible to maintain the line roller properly.